select.java

it is whiteboard sourse code

package org.merlin.step.nov;

import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class Select extends Component implements Tool, UpdateListener {
  public Select () {
    enableEvents (AWTEvent.MOUSE_EVENT_MASK | AWTEvent.MOUSE_MOTION_EVENT_MASK);
  }

  ObservableList elements;
  
  public void setDisplayList (ObservableList l) {
    elements = l;
    elements.addUpdateListener (this);
  }

  public Component getDisplay () {
    return this;
  }

  public Component getControls () {
    LWContainer controls = new LWContainer ();
    controls.setLayout (new BorderLayout ());
    controls.add ("North", new Label ("Select Tool", Label.CENTER));
    return controls;
  }

  public void dispose () {
    elements.removeUpdateListener (this);
  }

  public void updateOccurred (UpdateEvent e) {
    if (selected != null) {
      selected = null;
      repaint ();
    }
  }

  Element selected;
  int x0, y0, x1, y1;
    
  protected void processEvent (AWTEvent e) {
    super.processEvent (e);
    if (e instanceof MouseEvent) {
      MouseEvent m = (MouseEvent) e;
      switch (m.getID ()) {
        case MouseEvent.MOUSE_PRESSED:
          Element oSelected = selected;
          x0 = x1 = m.getX ();
          y0 = y1 = m.getY ();
          selected = null;
          Enumeration els = elements.elements ();
          while (els.hasMoreElements ()) {
            Element el = (Element) els.nextElement ();
            if ((el != null) && el.getBounds ().contains (x0, y0))
              selected = el;
          }
          if (selected != oSelected)
            repaint ();
          break;
        case MouseEvent.MOUSE_DRAGGED:
          if (selected != null) {
            x1 = m.getX ();
            y1 = m.getY ();
            repaint ();
          }
          break;
        case MouseEvent.MOUSE_RELEASED:
          if (selected != null) {
            x1 = m.getX ();
            y1 = m.getY ();
            elements.replaceElementAtEnd (selected, selected.getTranslated (x1 - x0, y1 - y0));
            selected = null;
            repaint ();
          }
          break;
      }
    }
  }

  public void paint (Graphics g) {
    if (selected != null) {
      Rectangle r = selected.getBounds ();
      g.setColor (Color.red);
      g.drawRect (r.x - 1 + x1 - x0, r.y - 1 + y1 - y0, r.width + 1, r.height + 1);
    }
  }
}